US 12,015,141 B2
Non-aqueous electrolyte secondary battery
Atsushi Obayashi, Sumoto (JP); and Hikaru Yoshida, Ibaraki (JP)
Assigned to Prime Planet Energy & Solutions, Inc., Tokyo (JP)
Filed by PRIME PLANET ENERGY & SOLUTIONS, INC., Tokyo (JP)
Filed on Sep. 24, 2021, as Appl. No. 17/484,070.
Claims priority of application No. 2020-178748 (JP), filed on Oct. 26, 2020.
Prior Publication US 2022/0131132 A1, Apr. 28, 2022
Int. Cl. H01M 4/139 (2010.01); H01M 4/02 (2006.01); H01M 4/04 (2006.01); H01M 10/05 (2010.01)
CPC H01M 4/139 (2013.01) [H01M 4/049 (2013.01); H01M 10/05 (2013.01); H01M 2004/021 (2013.01); H01M 2004/027 (2013.01)] 10 Claims
OG exemplary drawing
 
1. A non-aqueous electrolyte secondary battery comprising:
a positive electrode;
a negative electrode;
a separator; and
an electrolyte solution, wherein
at least part of the separator is interposed between the positive electrode and the negative electrode,
the negative electrode includes a negative electrode substrate and a negative electrode active material layer,
the negative electrode active material layer is placed on a surface of the negative electrode substrate,
in a cross section parallel to the thickness direction of the negative electrode active material layer, the negative electrode active material layer is divided into two equal parts in the thickness direction, and thus the negative electrode active material layer is separated into a first region and a second region,
the first region includes a surface of the negative electrode active material layer,
the second region includes an interface between the negative electrode active material layer and the negative electrode substrate,
the negative electrode active material layer includes a plurality of negative electrode active material particles,
each of the negative electrode active material particles consists of a negative electrode active material,
voids are formed in the first region of the negative electrode active material layer and in the second region of the negative electrode active material layer,
an average circularity of the voids in the first region of the negative electrode active material layer is 0.26 or more, and an average circularity of the voids in the second region of the negative electrode active material layer is less than 0.26,
each of the voids is surrounded by the plurality of negative electrode active material particles, and
in a cross section parallel to a thickness direction of the negative electrode active material layer,
the voids have:
an average equivalent circle diameter from 9.6 μm to 35.8 μm; and
an area percentage from 3.1% to 30.9%.